( 566 ) 
electricity, but has some features in common with it. In order to 
obtain a theory of this kind, I shall start from an idea that has been 
suggested long ago by Mossortr and has been afterwards accepted 
by WILHELM WEBER and ZÖLLNER. 
According to these physicists, every particle of ponderable matter 
consists of two oppositely electrified particles. Thus, between two par- 
ticles of matter, there will be four electric forces, two attractions 
between the charges of different, and two repulsions between those 
of equal signs. Mossorrr supposes the attractions to be somewhat 
greater than the repulsions, the difference between the two being 
precisely what we call gravitation. It is easily seen that such a 
difference might exist in cases where an action of a specific electric 
nature is not exerted. — 
Now, if the form of this theory is to be brought into harmony 
with the present state of electrical science, we must regard the four 
forees of Mossorti as the effect of certain states in the aether which 
are called forth by the positive and negative ions. 
A positive ion, as well as a negative one, is the centre of a 
dielectric displacement, and, in treating of electrical phenomena, these 
two displacements are considered as being of the same nature, so 
that, if in opposite directions and of equal magnitude, they wholly 
destroy each other. 
If gravitation is to be included in the theory, this view must be 
modified. Indeed, if the actions exerted by positive and negative 
ions depended on vector-quantities of the same kind, in such a 
way that all phenomena in the neighbourhood of a pair of ions 
with opposite charges were determined by the resulting vector, then 
electric actions could only be absent, if this resulting vector were 
0, but, if such were the case, no other actions could exist; a gravi- 
tation, i.e. a force in the absence of an electric field, would be 
impossible. 
I shall therefore suppose that the two disturbances in the acther, 
produced by positive and negative ions, are of a somewhat different 
nature, so that, even if they are represented in a diagram by equal 
and opposite vectors, the state of the aether is not the natural one. 
This corresponds in a sense to Mossorti’s idea that positive and 
negative charges differ from each other to a larger extent, than may 
be expressed by the signs + and —. 
After having attributed to each of the two states an independent 
and separate existence, we may assume that, though both able to 
act on positive and negative ions, the one has more power over the 
positive particles and the other over the negative ones. This diffe- 
